Restructuring Site - Retain SEO

I am planning to restructure my site slightly which means certain urls will be changing.

I rank quite well for some of these pages in google. What can I do to retain this once I change the url’s?

You need to work on link building, do not worry about changing url, but take care of link building.

I am restructuring my site so the links will be changing.

I want to know how I can minimise any impact this will have on my rankings.

Once you change the urls then it’s like starting over because its like a new page to google.